Add note about Buffer abstraction

lib/net.js

@@ -10,8 +10,16 @@ function debug () {
 
 var binding = process.binding('net');
 
-
+// Note about Buffer interface:
+// I'm attempting to do the simplest possible interface to abstracting raw
+// memory allocation. This might turn out to be too simple - it seems that
+// I always use a buffer.used member to keep track of how much I've filled.
+// Perhaps giving the Buffer a file-like interface with a head (which would
+// represent buffer.used) that can be seeked around would be easier. I'm not
+// yet convinced that every use-case can be fit into that abstraction, so
+// waiting to implement it until I get more experience with this.
 var Buffer      = process.Buffer;
+
 var IOWatcher   = process.IOWatcher;
 var assert      = process.assert;